1. Field of the Invention
The present invention relates to slide fasteners, and more particularly to a separable slide fastener.
2. Description of the Prior Art
In separable slide fasteners of the type in which a pair of top end stops is to be substantially completely received in a pair of branches of a Y-shaped guide channel in a slider when the latter is moved all the way up to fully close the slide fastener, there was a problem that the slider would be accidentally removed from one fastener stringer after the latter has been separated from the other fastener stringer. To this end, solutions have been proposed in U.S. Pat. No. 2,193,827 and Japanese Patent Laid-Open Publication (Kokai) No. 60-112909, for example.
According to the solution disclosed in U.S. Pat. No. 2,193,827, each top end stop has on its upper surface a projection, and the slider has in an inside surface of the respective branch of the Y-shaped channel a dead-end groove opening to the front end of the slider for slidably receiving the projection of the respective top end stop so as to restrict downward or rearward movement of the respective top end stop through the slider. This prior art slide fastener is disadvantageous in that the slider cannot be removed from the fastener stringers even when it is necessary for replacement with another or for facilitating attachment of the fastener stringers to a garment.
According to the solution disclosed in Japanese Patent Laid-Open Publication No. 61-112909, the slider has at its flaring front end of the Y-shaped guide channel chamferred surfaces, and each top end stop is made of synthetic resin and has at least one integral projection engageable with the chamferred surfaces. The projection is resiliently deformable as compressed by the chamferred surfaces when the slider is pulled forwardly over the top end stop with relatively great force. With this resiliently deformable projection, the top end stop is not only prevented from accidental removal from the fastener stringer but also allowed to be removed therefrom when necessary for replacement or other purposes. A problem with this prior art slide fastener is that the projection is relatively large in height in order to secure safety from accidental removal, causing an increased degree of friction between the slider and the top end stop while the latter is moved through one branch of the guide channel. With this increase of the friction, easy removal of the slider is difficult to achieve. Further, the material for the top end stops of this prior art slide fastener is limited to a special synthetic resin having a good resiliency.